The present invention relates to circular sawing systems in lumber mills, and more specifically to improvements in cutting performance of circular saws to provide improved lumber tolerances.
The cutting performance of circular rip saws has been improved dramatically in recent years due to the introduction of guides which provide the circular saw with lateral support to prevent or reduce deflection while sawing. Almost all circular saw guides employed in industrial operations are single guide blocks which support the saw blade either above or below the work piece. The support of the saw blade can be further increased by using double or triple guide systems. The benefits of multiple guides over single guides have been demonstrated theoretically, however the attempts to develop multiple guide systems and their implementation has not been as successful as expected. Alternatively the alignment of multiple guides has proved to be difficult.
One example of a type of circular saw blade guide and vibration damper is disclosed in my co-pending application Ser. No. 143,190. Now U.S. Pat. No. 4,854,207 housing with guide block specifically mounted to engage both faces of a saw blade. The guide blocks are resiliently biased against stops by pneumatic pressure to guide and dampen any vibration that occurs in the saw blade.
In standard gang edger operations it is found that when saw blades are either stationary or below operational speed, they may not be flat due to tensioning of the saw blade which is applied by rolling or hammering with the purpose of increasing the stiffness of the blade. This is specifically true for thin blades which deflect more easily.
At present, stationary double or triple guides are aligned manually and generally while the saw blades are not rotating. Thus a saw blade that is not flat gives a slight misalignment and this is detrimental to the cutting accuracy of the blade. Furthermore misalignment produces side forces which add to the lateral forces generated by the work piece and this again results in inaccuracies in the cutting.